Angular University has a good, step by step, tutorial on publishing an Angular 2 library to npm that addresses your concerns/questions.

You can provide a bundled and unbundled version if you wish, I would always provide an unbundled version though. In my libraries I do not provide a bundled version and leave it up to the consumer to bundle and minify.

http://blog.angular-university.io/how-to-create-an-angular-2-library-and-how-to-consume-it-jspm-vs-webpack/

Updated answer

The following steps will go through the process of creating, testing and publishing an unbundled angular module for consumption by a consumer using a bundler (webpack, angular cli, etc). For a more complete answer which includes bundling, see @OleksiiTrekhleb's answer.

Publishing an angular 2 library can be intimidating, but when it comes down it it's really no different than publish any other package on NPM. The following information will use the folder structure:

• package root
  • src
  • dist

1. Setting up tsconfig.json

As with any typescript library you want to have the declaration option set to true in your tsconfig.json under compilerOptions to ensure our consumers can take advantage of types within our package:

"declaration": true

In compilerOptions we also want to specify our outDir to keep transpiled code separate from the source:

"outDir": "./dist"

We want the include option to point to our source folder (note include is a sibling in relation to compilerOptions):

"include": [
  "./src"
]

Enable the experimental decorator options under compilerOptions:

"experimentalDecorators": true,
"emitDecoratorMetadata": true 

To avoid some errors when transpiling, you will need to enable skipLibCheck as well:

"skipLibCheck": true

Result

{
  "compilerOptions": {
    "target": "es5",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', or 'ESNEXT'. */
    "module": "commonjs",                     /* Specify module code generation: 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
    "skipLibCheck": true,
    "declaration": true,                   /* Generates corresponding '.d.ts' file. */
    "outDir": "./dist",                        /* Redirect output structure to the directory. */
    "strict": true,                            /* Enable all strict type-checking options. */
    "experimentalDecorators": true,        /* Enables experimental support for ES7 decorators. */
    "emitDecoratorMetadata": true         /* Enables experimental support for emitting type metadata for decorators. */
  },
  "include": [
    "./src"
  ]
}

2. The Module

This example will use a module with a single component. The component is fairly straight forward:

./src/helloWorld/helloWorld.component.ts

import { Component } from "@angular/core";

@Component({
    selector: 'hello-world',
    template: '<div>Hello, world</div>'
})
export class HelloWorldComponent {

}

The module should add consumable components to declarations and exports. We need to add to exports so when consumers import our module, they can use our components as well.

./src/helloWorld/helloWorld.module.ts

import { NgModule } from '@angular/core'
import { HelloWorldComponent } from './helloWorld.component';

const components: any[] = [
    HelloWorldComponent
];

@NgModule({
    declarations: components,
    exports: components // Don't forget to export!
})
export class HelloWorldModule {

}

3. The barrel

To simplify importing our modules we use a barrel, which file that exports everything to be consumed by our consumers.

./src/index.ts

export { HelloWorldModule } from './helloWorld/helloWorld.module';
export { HelloWorldComponent } from './helloWorld/helloWorld.component';

4. Setting up NPM

Package.json

In package.json, change the main property to point to our transpiled barrel, ./dist/index.js. Also add the typings property to point to our barrels definition file ./dist/index.d.ts.

Add the property prepublish under scripts in your package.json.

"scripts": {
    "prepublish": "tsc"
}

Also note that your angular and related dependencies should be under peerDependencies and not dependencies

NPM Ignore

Create a .npmignore file in the root of your package and ignore the src folder and any other files you do not want published with your package

src/
*.log

5. Testing

You can easily test your npm packages locally with npm link. In your module package folder, run the command npm link.

Then in your test project, run the command npm link <my package name>

Now you can import your module and add it to your test projects imports without having to publish.

6. Publishing

Your package can now be published with a simple npm publish